I'm a university student and have some experience with GIS but not loads. For my dissertation I am measuring beach profiles, using a dumpy level surveying technique, of some nesting habitats for the hawksbill sea turtle in order to determine how they will be affected by future changes in sea level.

How do I change data that is currently in the form in the picture (aka, point 2.2 is 10.5 meters along the beach and 5 meters up a transect, with height 0.669m above mean sea level)raw data collected in beach profiling into an x y z coordinate system that will be usable in a GIS program to create a triangulated irregular network?

I have a GPS measurement for the start point of my profiling.

For an example of what I am trying to do see Fish et al. 2005, Predicting the Impact of Sea-Level Rise on Caribbean Sea Turtle Nesting Habitat. Conservation Biology Vol. 19 (pp, 482-491).

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    Welcome to GIS SE! As a new user be sure to take the Tour to learn about our focussed Q&A format. I recommend not thinking about GIS SE as being some sort of online GIS tutor. For your questions to be answered here they should as much as possible describe not just what you want to do, but precisely what you have tried and where you are stuck trying that. What GIS program are you using? – PolyGeo Aug 21 '17 at 5:42
  • If you upload a sample matrix or table, including which software are you thinking, users of this site will help you – aldo_tapia Aug 21 '17 at 17:48
  • what data format do you have? – Mapperz Aug 21 '17 at 20:28
  • @Mapperz I have updated my question now so you can see what format my data is currently in. I am planning on using ArcGIS. – Julia Ganis Aug 22 '17 at 5:55
  • So what is stopping you from calculating the two missing coordinates? Also, the data from the table you cite is not visible in it, so it just makes thing more confusing. – lynxlynxlynx Aug 22 '17 at 10:27

Ok, I'll try to unwrap this a bit.

First thing that appears to cause you confusion is that you have the start point location in degrees and you can't just add or subtract meters from it. Most GIS programs allow you to reproject your data, so just look up which coordinate systems are in use in your area and pick one that uses meters. Reproject and your starting points will be expressed in meters, ready to be applied to the measured points.

Elevation (Z) is easy, as you already have it as an absolute number. X and Y on the other hand look impossible, since you haven't measured any angles — unless more of your method is not presented. In other words, how do you know in which direction to account for the distance along the beach and transect length? The distances are small, so you could estimate from a detailed map or a revisit, but it definitely won't be robust.

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  • Hi @lynxlynxlynx, thanks for your answer! For X and Y (since you are right I should've been measuring angles and from now on will do this) however for now I will use triangulation and trigonometry since I have 3 sides of all triangles in a sense to work out the angles. Will also use a map to then check this. – Julia Ganis Aug 24 '17 at 22:42

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